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llvm-project/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

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//===-- llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp --*- C++ -*--===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains support for writing Microsoft CodeView debug info.
//
//===----------------------------------------------------------------------===//
#include "CodeViewDebug.h"
#include "llvm/DebugInfo/CodeView/CodeView.h"
#include "llvm/DebugInfo/CodeView/Line.h"
#include "llvm/DebugInfo/CodeView/SymbolRecord.h"
#include "llvm/DebugInfo/CodeView/TypeIndex.h"
#include "llvm/DebugInfo/CodeView/TypeRecord.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/COFF.h"
#include "llvm/Target/TargetSubtargetInfo.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Target/TargetFrameLowering.h"
using namespace llvm;
using namespace llvm::codeview;
CodeViewDebug::CodeViewDebug(AsmPrinter *AP)
: DebugHandlerBase(AP), OS(*Asm->OutStreamer), CurFn(nullptr) {
// If module doesn't have named metadata anchors or COFF debug section
// is not available, skip any debug info related stuff.
if (!MMI->getModule()->getNamedMetadata("llvm.dbg.cu") ||
!AP->getObjFileLowering().getCOFFDebugSymbolsSection()) {
Asm = nullptr;
return;
}
// Tell MMI that we have debug info.
MMI->setDebugInfoAvailability(true);
}
StringRef CodeViewDebug::getFullFilepath(const DIFile *File) {
std::string &Filepath = FileToFilepathMap[File];
if (!Filepath.empty())
return Filepath;
StringRef Dir = File->getDirectory(), Filename = File->getFilename();
// Clang emits directory and relative filename info into the IR, but CodeView
// operates on full paths. We could change Clang to emit full paths too, but
// that would increase the IR size and probably not needed for other users.
// For now, just concatenate and canonicalize the path here.
if (Filename.find(':') == 1)
Filepath = Filename;
else
Filepath = (Dir + "\\" + Filename).str();
// Canonicalize the path. We have to do it textually because we may no longer
// have access the file in the filesystem.
// First, replace all slashes with backslashes.
std::replace(Filepath.begin(), Filepath.end(), '/', '\\');
// Remove all "\.\" with "\".
size_t Cursor = 0;
while ((Cursor = Filepath.find("\\.\\", Cursor)) != std::string::npos)
Filepath.erase(Cursor, 2);
// Replace all "\XXX\..\" with "\". Don't try too hard though as the original
// path should be well-formatted, e.g. start with a drive letter, etc.
Cursor = 0;
while ((Cursor = Filepath.find("\\..\\", Cursor)) != std::string::npos) {
// Something's wrong if the path starts with "\..\", abort.
if (Cursor == 0)
break;
size_t PrevSlash = Filepath.rfind('\\', Cursor - 1);
if (PrevSlash == std::string::npos)
// Something's wrong, abort.
break;
Filepath.erase(PrevSlash, Cursor + 3 - PrevSlash);
// The next ".." might be following the one we've just erased.
Cursor = PrevSlash;
}
// Remove all duplicate backslashes.
Cursor = 0;
while ((Cursor = Filepath.find("\\\\", Cursor)) != std::string::npos)
Filepath.erase(Cursor, 1);
return Filepath;
}
unsigned CodeViewDebug::maybeRecordFile(const DIFile *F) {
unsigned NextId = FileIdMap.size() + 1;
auto Insertion = FileIdMap.insert(std::make_pair(F, NextId));
if (Insertion.second) {
// We have to compute the full filepath and emit a .cv_file directive.
StringRef FullPath = getFullFilepath(F);
NextId = OS.EmitCVFileDirective(NextId, FullPath);
assert(NextId == FileIdMap.size() && ".cv_file directive failed");
}
return Insertion.first->second;
}
CodeViewDebug::InlineSite &
CodeViewDebug::getInlineSite(const DILocation *InlinedAt,
const DISubprogram *Inlinee) {
auto SiteInsertion = CurFn->InlineSites.insert({InlinedAt, InlineSite()});
InlineSite *Site = &SiteInsertion.first->second;
if (SiteInsertion.second) {
Site->SiteFuncId = NextFuncId++;
Site->Inlinee = Inlinee;
auto InlineeInsertion =
SubprogramIndices.insert({Inlinee, InlinedSubprograms.size()});
if (InlineeInsertion.second)
InlinedSubprograms.push_back(Inlinee);
}
return *Site;
}
void CodeViewDebug::recordLocalVariable(LocalVariable &&Var,
const DILocation *InlinedAt) {
if (InlinedAt) {
// This variable was inlined. Associate it with the InlineSite.
const DISubprogram *Inlinee = Var.DIVar->getScope()->getSubprogram();
InlineSite &Site = getInlineSite(InlinedAt, Inlinee);
Site.InlinedLocals.emplace_back(Var);
} else {
// This variable goes in the main ProcSym.
CurFn->Locals.emplace_back(Var);
}
}
static void addLocIfNotPresent(SmallVectorImpl<const DILocation *> &Locs,
const DILocation *Loc) {
auto B = Locs.begin(), E = Locs.end();
if (std::find(B, E, Loc) == E)
Locs.push_back(Loc);
}
void CodeViewDebug::maybeRecordLocation(DebugLoc DL,
const MachineFunction *MF) {
// Skip this instruction if it has the same location as the previous one.
if (DL == CurFn->LastLoc)
return;
const DIScope *Scope = DL.get()->getScope();
if (!Scope)
return;
// Skip this line if it is longer than the maximum we can record.
LineInfo LI(DL.getLine(), DL.getLine(), /*IsStatement=*/true);
if (LI.getStartLine() != DL.getLine() || LI.isAlwaysStepInto() ||
LI.isNeverStepInto())
return;
ColumnInfo CI(DL.getCol(), /*EndColumn=*/0);
if (CI.getStartColumn() != DL.getCol())
return;
if (!CurFn->HaveLineInfo)
CurFn->HaveLineInfo = true;
unsigned FileId = 0;
if (CurFn->LastLoc.get() && CurFn->LastLoc->getFile() == DL->getFile())
FileId = CurFn->LastFileId;
else
FileId = CurFn->LastFileId = maybeRecordFile(DL->getFile());
CurFn->LastLoc = DL;
unsigned FuncId = CurFn->FuncId;
if (const DILocation *SiteLoc = DL->getInlinedAt()) {
const DILocation *Loc = DL.get();
// If this location was actually inlined from somewhere else, give it the ID
// of the inline call site.
FuncId =
getInlineSite(SiteLoc, Loc->getScope()->getSubprogram()).SiteFuncId;
// Ensure we have links in the tree of inline call sites.
bool FirstLoc = true;
while ((SiteLoc = Loc->getInlinedAt())) {
InlineSite &Site =
getInlineSite(SiteLoc, Loc->getScope()->getSubprogram());
if (!FirstLoc)
addLocIfNotPresent(Site.ChildSites, Loc);
FirstLoc = false;
Loc = SiteLoc;
}
addLocIfNotPresent(CurFn->ChildSites, Loc);
}
OS.EmitCVLocDirective(FuncId, FileId, DL.getLine(), DL.getCol(),
/*PrologueEnd=*/false,
/*IsStmt=*/false, DL->getFilename());
}
void CodeViewDebug::endModule() {
if (FnDebugInfo.empty())
return;
emitTypeInformation();
// FIXME: For functions that are comdat, we should emit separate .debug$S
// sections that are comdat associative with the main function instead of
// having one big .debug$S section.
assert(Asm != nullptr);
OS.SwitchSection(Asm->getObjFileLowering().getCOFFDebugSymbolsSection());
OS.AddComment("Debug section magic");
OS.EmitIntValue(COFF::DEBUG_SECTION_MAGIC, 4);
// The COFF .debug$S section consists of several subsections, each starting
// with a 4-byte control code (e.g. 0xF1, 0xF2, etc) and then a 4-byte length
// of the payload followed by the payload itself. The subsections are 4-byte
// aligned.
// Make a subsection for all the inlined subprograms.
emitInlineeFuncIdsAndLines();
// Emit per-function debug information.
for (auto &P : FnDebugInfo)
emitDebugInfoForFunction(P.first, P.second);
// This subsection holds a file index to offset in string table table.
OS.AddComment("File index to string table offset subsection");
OS.EmitCVFileChecksumsDirective();
// This subsection holds the string table.
OS.AddComment("String table");
OS.EmitCVStringTableDirective();
clear();
}
static void emitNullTerminatedSymbolName(MCStreamer &OS, StringRef S) {
// Microsoft's linker seems to have trouble with symbol names longer than
// 0xffd8 bytes.
S = S.substr(0, 0xffd8);
SmallString<32> NullTerminatedString(S);
NullTerminatedString.push_back('\0');
OS.EmitBytes(NullTerminatedString);
}
void CodeViewDebug::emitTypeInformation() {
// Do nothing if we have no debug info or no inlined subprograms. The types
// we currently emit exist only to support inlined call site info.
NamedMDNode *CU_Nodes =
MMI->getModule()->getNamedMetadata("llvm.dbg.cu");
if (!CU_Nodes)
return;
if (InlinedSubprograms.empty())
return;
// Start the .debug$T section with 0x4.
OS.SwitchSection(Asm->getObjFileLowering().getCOFFDebugTypesSection());
OS.AddComment("Debug section magic");
OS.EmitIntValue(COFF::DEBUG_SECTION_MAGIC, 4);
// This type info currently only holds function ids for use with inline call
// frame info. All functions are assigned a simple 'void ()' type. Emit that
// type here.
unsigned ArgListIndex = getNextTypeIndex();
OS.AddComment("Type record length");
OS.EmitIntValue(2 + sizeof(ArgList), 2);
OS.AddComment("Leaf type: LF_ARGLIST");
OS.EmitIntValue(LF_ARGLIST, 2);
OS.AddComment("Number of arguments");
OS.EmitIntValue(0, 4);
unsigned VoidFnTyIdx = getNextTypeIndex();
OS.AddComment("Type record length");
OS.EmitIntValue(2 + sizeof(ProcedureType), 2);
OS.AddComment("Leaf type: LF_PROCEDURE");
OS.EmitIntValue(LF_PROCEDURE, 2);
OS.AddComment("Return type index");
OS.EmitIntValue(TypeIndex::Void().getIndex(), 4);
OS.AddComment("Calling convention");
OS.EmitIntValue(char(CallingConvention::NearC), 1);
OS.AddComment("Function options");
OS.EmitIntValue(char(FunctionOptions::None), 1);
OS.AddComment("# of parameters");
OS.EmitIntValue(0, 2);
OS.AddComment("Argument list type index");
OS.EmitIntValue(ArgListIndex, 4);
// Emit LF_FUNC_ID records for all inlined subprograms to the type stream.
// Allocate one type index for each func id.
unsigned NextIdx = getNextTypeIndex(InlinedSubprograms.size());
(void)NextIdx;
assert(NextIdx == FuncIdTypeIndexStart && "func id type indices broken");
for (auto *SP : InlinedSubprograms) {
StringRef DisplayName = SP->getDisplayName();
OS.AddComment("Type record length");
MCSymbol *FuncBegin = MMI->getContext().createTempSymbol(),
*FuncEnd = MMI->getContext().createTempSymbol();
OS.emitAbsoluteSymbolDiff(FuncEnd, FuncBegin, 2);
OS.EmitLabel(FuncBegin);
OS.AddComment("Leaf type: LF_FUNC_ID");
OS.EmitIntValue(LF_FUNC_ID, 2);
OS.AddComment("Scope type index");
OS.EmitIntValue(0, 4);
OS.AddComment("Function type");
OS.EmitIntValue(VoidFnTyIdx, 4);
{
OS.AddComment("Function name");
emitNullTerminatedSymbolName(OS, DisplayName);
}
OS.EmitLabel(FuncEnd);
}
}
void CodeViewDebug::emitInlineeFuncIdsAndLines() {
if (InlinedSubprograms.empty())
return;
MCSymbol *InlineBegin = MMI->getContext().createTempSymbol(),
*InlineEnd = MMI->getContext().createTempSymbol();
OS.AddComment("Inlinee lines subsection");
OS.EmitIntValue(unsigned(ModuleSubstreamKind::InlineeLines), 4);
OS.AddComment("Subsection size");
OS.emitAbsoluteSymbolDiff(InlineEnd, InlineBegin, 4);
OS.EmitLabel(InlineBegin);
// We don't provide any extra file info.
// FIXME: Find out if debuggers use this info.
OS.AddComment("Inlinee lines signature");
OS.EmitIntValue(unsigned(InlineeLinesSignature::Normal), 4);
unsigned InlineeIndex = FuncIdTypeIndexStart;
for (const DISubprogram *SP : InlinedSubprograms) {
OS.AddBlankLine();
unsigned FileId = maybeRecordFile(SP->getFile());
OS.AddComment("Inlined function " + SP->getDisplayName() + " starts at " +
SP->getFilename() + Twine(':') + Twine(SP->getLine()));
OS.AddBlankLine();
// The filechecksum table uses 8 byte entries for now, and file ids start at
// 1.
unsigned FileOffset = (FileId - 1) * 8;
OS.AddComment("Type index of inlined function");
OS.EmitIntValue(InlineeIndex, 4);
OS.AddComment("Offset into filechecksum table");
OS.EmitIntValue(FileOffset, 4);
OS.AddComment("Starting line number");
OS.EmitIntValue(SP->getLine(), 4);
// The next inlined subprogram has the next function id.
InlineeIndex++;
}
OS.EmitLabel(InlineEnd);
}
void CodeViewDebug::collectInlineSiteChildren(
SmallVectorImpl<unsigned> &Children, const FunctionInfo &FI,
const InlineSite &Site) {
for (const DILocation *ChildSiteLoc : Site.ChildSites) {
auto I = FI.InlineSites.find(ChildSiteLoc);
const InlineSite &ChildSite = I->second;
Children.push_back(ChildSite.SiteFuncId);
collectInlineSiteChildren(Children, FI, ChildSite);
}
}
void CodeViewDebug::emitInlinedCallSite(const FunctionInfo &FI,
const DILocation *InlinedAt,
const InlineSite &Site) {
MCSymbol *InlineBegin = MMI->getContext().createTempSymbol(),
*InlineEnd = MMI->getContext().createTempSymbol();
assert(SubprogramIndices.count(Site.Inlinee));
unsigned InlineeIdx = FuncIdTypeIndexStart + SubprogramIndices[Site.Inlinee];
// SymbolRecord
OS.AddComment("Record length");
OS.emitAbsoluteSymbolDiff(InlineEnd, InlineBegin, 2); // RecordLength
OS.EmitLabel(InlineBegin);
OS.AddComment("Record kind: S_INLINESITE");
OS.EmitIntValue(SymbolRecordKind::S_INLINESITE, 2); // RecordKind
OS.AddComment("PtrParent");
OS.EmitIntValue(0, 4);
OS.AddComment("PtrEnd");
OS.EmitIntValue(0, 4);
OS.AddComment("Inlinee type index");
OS.EmitIntValue(InlineeIdx, 4);
unsigned FileId = maybeRecordFile(Site.Inlinee->getFile());
unsigned StartLineNum = Site.Inlinee->getLine();
SmallVector<unsigned, 3> SecondaryFuncIds;
collectInlineSiteChildren(SecondaryFuncIds, FI, Site);
OS.EmitCVInlineLinetableDirective(Site.SiteFuncId, FileId, StartLineNum,
FI.Begin, FI.End, SecondaryFuncIds);
OS.EmitLabel(InlineEnd);
for (const LocalVariable &Var : Site.InlinedLocals)
emitLocalVariable(Var);
// Recurse on child inlined call sites before closing the scope.
for (const DILocation *ChildSite : Site.ChildSites) {
auto I = FI.InlineSites.find(ChildSite);
assert(I != FI.InlineSites.end() &&
"child site not in function inline site map");
emitInlinedCallSite(FI, ChildSite, I->second);
}
// Close the scope.
OS.AddComment("Record length");
OS.EmitIntValue(2, 2); // RecordLength
OS.AddComment("Record kind: S_INLINESITE_END");
OS.EmitIntValue(SymbolRecordKind::S_INLINESITE_END, 2); // RecordKind
}
void CodeViewDebug::emitDebugInfoForFunction(const Function *GV,
FunctionInfo &FI) {
// For each function there is a separate subsection
// which holds the PC to file:line table.
const MCSymbol *Fn = Asm->getSymbol(GV);
assert(Fn);
StringRef FuncName;
if (auto *SP = GV->getSubprogram())
FuncName = SP->getDisplayName();
// If our DISubprogram name is empty, use the mangled name.
if (FuncName.empty())
FuncName = GlobalValue::getRealLinkageName(GV->getName());
// Emit a symbol subsection, required by VS2012+ to find function boundaries.
MCSymbol *SymbolsBegin = MMI->getContext().createTempSymbol(),
*SymbolsEnd = MMI->getContext().createTempSymbol();
OS.AddComment("Symbol subsection for " + Twine(FuncName));
OS.EmitIntValue(unsigned(ModuleSubstreamKind::Symbols), 4);
OS.AddComment("Subsection size");
OS.emitAbsoluteSymbolDiff(SymbolsEnd, SymbolsBegin, 4);
OS.EmitLabel(SymbolsBegin);
{
MCSymbol *ProcRecordBegin = MMI->getContext().createTempSymbol(),
*ProcRecordEnd = MMI->getContext().createTempSymbol();
OS.AddComment("Record length");
OS.emitAbsoluteSymbolDiff(ProcRecordEnd, ProcRecordBegin, 2);
OS.EmitLabel(ProcRecordBegin);
OS.AddComment("Record kind: S_GPROC32_ID");
OS.EmitIntValue(unsigned(SymbolRecordKind::S_GPROC32_ID), 2);
// These fields are filled in by tools like CVPACK which run after the fact.
OS.AddComment("PtrParent");
OS.EmitIntValue(0, 4);
OS.AddComment("PtrEnd");
OS.EmitIntValue(0, 4);
OS.AddComment("PtrNext");
OS.EmitIntValue(0, 4);
// This is the important bit that tells the debugger where the function
// code is located and what's its size:
OS.AddComment("Code size");
OS.emitAbsoluteSymbolDiff(FI.End, Fn, 4);
OS.AddComment("Offset after prologue");
OS.EmitIntValue(0, 4);
OS.AddComment("Offset before epilogue");
OS.EmitIntValue(0, 4);
OS.AddComment("Function type index");
OS.EmitIntValue(0, 4);
OS.AddComment("Function section relative address");
OS.EmitCOFFSecRel32(Fn);
OS.AddComment("Function section index");
OS.EmitCOFFSectionIndex(Fn);
OS.AddComment("Flags");
OS.EmitIntValue(0, 1);
// Emit the function display name as a null-terminated string.
OS.AddComment("Function name");
// Truncate the name so we won't overflow the record length field.
emitNullTerminatedSymbolName(OS, FuncName);
OS.EmitLabel(ProcRecordEnd);
for (const LocalVariable &Var : FI.Locals)
emitLocalVariable(Var);
// Emit inlined call site information. Only emit functions inlined directly
// into the parent function. We'll emit the other sites recursively as part
// of their parent inline site.
for (const DILocation *InlinedAt : FI.ChildSites) {
auto I = FI.InlineSites.find(InlinedAt);
assert(I != FI.InlineSites.end() &&
"child site not in function inline site map");
emitInlinedCallSite(FI, InlinedAt, I->second);
}
// We're done with this function.
OS.AddComment("Record length");
OS.EmitIntValue(0x0002, 2);
OS.AddComment("Record kind: S_PROC_ID_END");
OS.EmitIntValue(unsigned(SymbolRecordKind::S_PROC_ID_END), 2);
}
OS.EmitLabel(SymbolsEnd);
// Every subsection must be aligned to a 4-byte boundary.
OS.EmitValueToAlignment(4);
// We have an assembler directive that takes care of the whole line table.
OS.EmitCVLinetableDirective(FI.FuncId, Fn, FI.End);
}
CodeViewDebug::LocalVarDefRange
CodeViewDebug::createDefRangeMem(uint16_t CVRegister, int Offset) {
LocalVarDefRange DR;
DR.InMemory = -1;
DR.DataOffset = Offset;
assert(DR.DataOffset == Offset && "truncation");
DR.StructOffset = 0;
DR.CVRegister = CVRegister;
return DR;
}
CodeViewDebug::LocalVarDefRange
CodeViewDebug::createDefRangeReg(uint16_t CVRegister) {
LocalVarDefRange DR;
DR.InMemory = 0;
DR.DataOffset = 0;
DR.StructOffset = 0;
DR.CVRegister = CVRegister;
return DR;
}
void CodeViewDebug::collectVariableInfoFromMMITable(
DenseSet<InlinedVariable> &Processed) {
const TargetSubtargetInfo &TSI = Asm->MF->getSubtarget();
const TargetFrameLowering *TFI = TSI.getFrameLowering();
const TargetRegisterInfo *TRI = TSI.getRegisterInfo();
for (const MachineModuleInfo::VariableDbgInfo &VI :
MMI->getVariableDbgInfo()) {
if (!VI.Var)
continue;
assert(VI.Var->isValidLocationForIntrinsic(VI.Loc) &&
"Expected inlined-at fields to agree");
Processed.insert(InlinedVariable(VI.Var, VI.Loc->getInlinedAt()));
LexicalScope *Scope = LScopes.findLexicalScope(VI.Loc);
// If variable scope is not found then skip this variable.
if (!Scope)
continue;
// Get the frame register used and the offset.
unsigned FrameReg = 0;
int FrameOffset = TFI->getFrameIndexReference(*Asm->MF, VI.Slot, FrameReg);
uint16_t CVReg = TRI->getCodeViewRegNum(FrameReg);
// Calculate the label ranges.
LocalVarDefRange DefRange = createDefRangeMem(CVReg, FrameOffset);
for (const InsnRange &Range : Scope->getRanges()) {
const MCSymbol *Begin = getLabelBeforeInsn(Range.first);
const MCSymbol *End = getLabelAfterInsn(Range.second);
End = End ? End : Asm->getFunctionEnd();
DefRange.Ranges.emplace_back(Begin, End);
}
LocalVariable Var;
Var.DIVar = VI.Var;
Var.DefRanges.emplace_back(std::move(DefRange));
recordLocalVariable(std::move(Var), VI.Loc->getInlinedAt());
}
}
void CodeViewDebug::collectVariableInfo(const DISubprogram *SP) {
DenseSet<InlinedVariable> Processed;
// Grab the variable info that was squirreled away in the MMI side-table.
collectVariableInfoFromMMITable(Processed);
const TargetRegisterInfo *TRI = Asm->MF->getSubtarget().getRegisterInfo();
for (const auto &I : DbgValues) {
InlinedVariable IV = I.first;
if (Processed.count(IV))
continue;
const DILocalVariable *DIVar = IV.first;
const DILocation *InlinedAt = IV.second;
// Instruction ranges, specifying where IV is accessible.
const auto &Ranges = I.second;
LexicalScope *Scope = nullptr;
if (InlinedAt)
Scope = LScopes.findInlinedScope(DIVar->getScope(), InlinedAt);
else
Scope = LScopes.findLexicalScope(DIVar->getScope());
// If variable scope is not found then skip this variable.
if (!Scope)
continue;
LocalVariable Var;
Var.DIVar = DIVar;
// Calculate the definition ranges.
for (auto I = Ranges.begin(), E = Ranges.end(); I != E; ++I) {
const InsnRange &Range = *I;
const MachineInstr *DVInst = Range.first;
assert(DVInst->isDebugValue() && "Invalid History entry");
const DIExpression *DIExpr = DVInst->getDebugExpression();
// Bail if there is a complex DWARF expression for now.
if (DIExpr && DIExpr->getNumElements() > 0)
continue;
// Bail if operand 0 is not a valid register. This means the variable is a
// simple constant, or is described by a complex expression.
// FIXME: Find a way to represent constant variables, since they are
// relatively common.
unsigned Reg =
DVInst->getOperand(0).isReg() ? DVInst->getOperand(0).getReg() : 0;
if (Reg == 0)
continue;
// Handle the two cases we can handle: indirect in memory and in register.
bool IsIndirect = DVInst->getOperand(1).isImm();
unsigned CVReg = TRI->getCodeViewRegNum(DVInst->getOperand(0).getReg());
{
LocalVarDefRange DefRange;
if (IsIndirect) {
int64_t Offset = DVInst->getOperand(1).getImm();
DefRange = createDefRangeMem(CVReg, Offset);
} else {
DefRange = createDefRangeReg(CVReg);
}
if (Var.DefRanges.empty() ||
Var.DefRanges.back().isDifferentLocation(DefRange)) {
Var.DefRanges.emplace_back(std::move(DefRange));
}
}
// Compute the label range.
const MCSymbol *Begin = getLabelBeforeInsn(Range.first);
const MCSymbol *End = getLabelAfterInsn(Range.second);
if (!End) {
if (std::next(I) != E)
End = getLabelBeforeInsn(std::next(I)->first);
else
End = Asm->getFunctionEnd();
}
// If the last range end is our begin, just extend the last range.
// Otherwise make a new range.
SmallVectorImpl<std::pair<const MCSymbol *, const MCSymbol *>> &Ranges =
Var.DefRanges.back().Ranges;
if (!Ranges.empty() && Ranges.back().second == Begin)
Ranges.back().second = End;
else
Ranges.emplace_back(Begin, End);
// FIXME: Do more range combining.
}
recordLocalVariable(std::move(Var), InlinedAt);
}
}
void CodeViewDebug::beginFunction(const MachineFunction *MF) {
assert(!CurFn && "Can't process two functions at once!");
if (!Asm || !MMI->hasDebugInfo())
return;
DebugHandlerBase::beginFunction(MF);
const Function *GV = MF->getFunction();
assert(FnDebugInfo.count(GV) == false);
CurFn = &FnDebugInfo[GV];
CurFn->FuncId = NextFuncId++;
CurFn->Begin = Asm->getFunctionBegin();
// Find the end of the function prolog. First known non-DBG_VALUE and
// non-frame setup location marks the beginning of the function body.
// FIXME: is there a simpler a way to do this? Can we just search
// for the first instruction of the function, not the last of the prolog?
DebugLoc PrologEndLoc;
bool EmptyPrologue = true;
for (const auto &MBB : *MF) {
for (const auto &MI : MBB) {
if (!MI.isDebugValue() && !MI.getFlag(MachineInstr::FrameSetup) &&
MI.getDebugLoc()) {
PrologEndLoc = MI.getDebugLoc();
break;
} else if (!MI.isDebugValue()) {
EmptyPrologue = false;
}
}
}
// Record beginning of function if we have a non-empty prologue.
if (PrologEndLoc && !EmptyPrologue) {
DebugLoc FnStartDL = PrologEndLoc.getFnDebugLoc();
maybeRecordLocation(FnStartDL, MF);
}
}
void CodeViewDebug::emitLocalVariable(const LocalVariable &Var) {
// LocalSym record, see SymbolRecord.h for more info.
MCSymbol *LocalBegin = MMI->getContext().createTempSymbol(),
*LocalEnd = MMI->getContext().createTempSymbol();
OS.AddComment("Record length");
OS.emitAbsoluteSymbolDiff(LocalEnd, LocalBegin, 2);
OS.EmitLabel(LocalBegin);
OS.AddComment("Record kind: S_LOCAL");
OS.EmitIntValue(unsigned(SymbolRecordKind::S_LOCAL), 2);
uint16_t Flags = 0;
if (Var.DIVar->isParameter())
Flags |= LocalSym::IsParameter;
if (Var.DefRanges.empty())
Flags |= LocalSym::IsOptimizedOut;
OS.AddComment("TypeIndex");
OS.EmitIntValue(TypeIndex::Int32().getIndex(), 4);
OS.AddComment("Flags");
OS.EmitIntValue(Flags, 2);
// Truncate the name so we won't overflow the record length field.
emitNullTerminatedSymbolName(OS, Var.DIVar->getName());
OS.EmitLabel(LocalEnd);
// Calculate the on disk prefix of the appropriate def range record. The
// records and on disk formats are described in SymbolRecords.h. BytePrefix
// should be big enough to hold all forms without memory allocation.
SmallString<20> BytePrefix;
for (const LocalVarDefRange &DefRange : Var.DefRanges) {
BytePrefix.clear();
// FIXME: Handle bitpieces.
if (DefRange.StructOffset != 0)
continue;
if (DefRange.InMemory) {
DefRangeRegisterRelSym Sym{};
ulittle16_t SymKind = ulittle16_t(S_DEFRANGE_REGISTER_REL);
Sym.BaseRegister = DefRange.CVRegister;
Sym.Flags = 0; // Unclear what matters here.
Sym.BasePointerOffset = DefRange.DataOffset;
BytePrefix +=
StringRef(reinterpret_cast<const char *>(&SymKind), sizeof(SymKind));
BytePrefix += StringRef(reinterpret_cast<const char *>(&Sym),
sizeof(Sym) - sizeof(LocalVariableAddrRange));
} else {
assert(DefRange.DataOffset == 0 && "unexpected offset into register");
DefRangeRegisterSym Sym{};
ulittle16_t SymKind = ulittle16_t(S_DEFRANGE_REGISTER);
Sym.Register = DefRange.CVRegister;
Sym.MayHaveNoName = 0; // Unclear what matters here.
BytePrefix +=
StringRef(reinterpret_cast<const char *>(&SymKind), sizeof(SymKind));
BytePrefix += StringRef(reinterpret_cast<const char *>(&Sym),
sizeof(Sym) - sizeof(LocalVariableAddrRange));
}
OS.EmitCVDefRangeDirective(DefRange.Ranges, BytePrefix);
}
}
void CodeViewDebug::endFunction(const MachineFunction *MF) {
if (!Asm || !CurFn) // We haven't created any debug info for this function.
return;
const Function *GV = MF->getFunction();
assert(FnDebugInfo.count(GV));
assert(CurFn == &FnDebugInfo[GV]);
collectVariableInfo(GV->getSubprogram());
DebugHandlerBase::endFunction(MF);
// Don't emit anything if we don't have any line tables.
if (!CurFn->HaveLineInfo) {
FnDebugInfo.erase(GV);
CurFn = nullptr;
return;
}
CurFn->End = Asm->getFunctionEnd();
CurFn = nullptr;
}
void CodeViewDebug::beginInstruction(const MachineInstr *MI) {
DebugHandlerBase::beginInstruction(MI);
// Ignore DBG_VALUE locations and function prologue.
if (!Asm || MI->isDebugValue() || MI->getFlag(MachineInstr::FrameSetup))
return;
DebugLoc DL = MI->getDebugLoc();
if (DL == PrevInstLoc || !DL)
return;
maybeRecordLocation(DL, Asm->MF);
}
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